Outsourcing vs software: what's the most cost-effective payroll processing?

If you don't have too many employees it may make sense to acquire specialised software  and keep the work in house. But then again, you'll need to stay abreast of the latest pay reporting regulations and software developments. As you can see, your choice will depend largely on the sepcifics of your business. The best approach would be to ask for quotes from several providers and compare what they offer, and for how much.